Ground Lines

Maps guide us through unfamiliar terrain
Desert terrain north of Bishop, California (Photo: Bureau of Land Management)

Desert terrain north of Bishop, California (Photo: Bureau of Land Management)

I remember my first day at what’s called “baby field camp” in the Oregon State geology program. Outside Bishop, California, we mapped the area around a cinder cone, long since dead. I quickly learned that the hot sun is a never-ending force of nature, not to be underestimated. I drank at least a gallon of water every day. Professor Andrew Meigs gave me and two-dozen other students our task: Use the tools provided (field notebook, Brunton compass, rock hammer, hand lens and a contour map) to understand what happened to this brick-red hill in the middle of the desert.

Stepping over cacti (sit at your peril!) and even shards of obsidian from long-ago residents, I began training my eyes to notice important clues: the downward dip of cinder layers on the hill, the change in sediment and bedrock colors over distance. I used to overlook these subtle signs, but as I worked, they became critical. The rock hammer clanking on my belt and the hand lens hanging around my neck got me closer to small details, while my legs carried me around the landscape to understand the big picture. Above all, every observation from sediment color, rock composition and how far a layer inclined from horizontal had to be recorded in the orange field book and marked on the contour map.

The maps we created became the key to unraveling the cinder cone’s story. They enabled us to see a cross-section of the Earth under our feet, as though we had sliced down with an enormous knife and peeled the crust back to reveal its ancient face. We started to understand the Earth in three dimensions. We began to appreciate maps for what they are, our connection to the world beyond what we can experience directly through our five senses.

Those ten days in the Southern California desert opened my eyes. I learned how to challenge assumptions and drop expectations before coming to a conclusion about the history of a landscape, all through mapping. Above all, I learned that maps allow us to step back and gain perspective, illuminating patterns that we couldn’t see otherwise. The connections we make with maps produce solutions to some of our most pressing issues and even inspire discoveries. In more ways than one, maps provide a path through the unfamiliar, a priceless tool in such a dynamic world.

This love of maps shouldn’t be surprising for a budding geologist like me. Geology owes much of its existence to maps. In fact, the first geological map was created by a scientist who was intrigued by the coal seams of southeastern England. William Smith, a forefather of modern geology, developed the first geological map. He traveled on horseback, weighed down carriages with rock samples, meticulously wrote and re-wrote and deduced an explanation for the location, orientation and relative age of coal seams and strange figured stones (fossils) that no one understood.

Axial data revealing the N-S alignment in three ruminant species under study. (A) Cattle. (B) Roe deer. (C) Red deer. Each pair of dots (located on opposite sites within the unit circle) represents the direction of the axial mean vector of the animals' body position at one locality. The mean vector calculated over all localities of the respective species is indicated by the double-headed arrow. The length of the arrow represents the r-value (length of the mean vector), dotted circles indicate the 0.01-level of significance. Triangles positioned outside the unit circle indicate the mean vectors of the cattle data subdivided into the six continents (dotted: North America; gray: Asia; checkered: Europe; striped: Australia; black: Africa; white: South America) (A) and the mean vectors of resting (black) and grazing (white) deer, and of deer beds (dotted) (B: roe deer; C: red deer).

Google Earth provided satellite images on which these axial data reveal the N-S alignment in three ruminant species: (A) Cattle. (B) Roe deer. (C) Red deer. Each pair of dots (located on opposite sites within the unit circle) represents the direction of the axial mean vector of the animals' body position at one locality. (From Begall, et al, 2008, PNAS, Magnetic alignment in grazing and resting cattle and deer)

With his map, Smith brought a deeper understanding to the beautiful countryside so often admired in British culture. He showed that it has a history, a story different than that of biblical origin, the prevailing explanation for the landscape at the time. His studies directly created the science of stratigraphy, the study of rock layers, and with it the rest of geology. Above all, he demonstrated the amazing power of connection and the power of perspective that maps provide.

Today, old maps seem almost quaint. We have Google Earth, which led to one of my favorite discoveries, one involving cows. Researchers used satellite images from Google Earth to survey the orientation of cows and roe deer as they bedded down in locations around the world. The scientists found that, when these animals graze or rest, they tend to line up with magnetic north. This was unknown before the study. Map technology demonstrated an unseen biological property: the behavior of some animals correlates with the lines of force in the Earth’s magnetic field. This connection opens up myriad questions about familiar animals that I thought I understood. It also raises questions about what the Earth’s magnetic field does to the human species. Can it influence our biology? If so, how?

Map of Late Cretaceous coastline (85Ma). (Image from Paleogeography and Geologic Evolution of North America)

Map of Late Cretaceous coastline (85Ma). (Image from Paleogeography and Geologic Evolution of North America)

Maps even shed light on social and cultural head-scratchers. In the southern United States, there’s a peculiar ribbon of counties across Alabama, Georgia and South Carolina that tend to vote Democratic in presidential elections. Prior to the 1965 Voting Rights Act, this pattern didn’t exist. Most black people did not vote. When researchers overlaid a geological map on the 2000, 2004 and 2008 county-by-county voting census, an intriguing picture came to light. During the Cretaceous Period (145-65 million years ago), the area to become Alabama, Georgia, and South Carolina occupied the coastline of a tropical sea. Warm, shallow waters rich in organic material lapped the shore. The life and death of unfathomable numbers of plankton and other marine organisms produced vast deposits of chalk, which formed the basis for the cotton industry that boomed in America 65 million years later. After the end of voter discrimination nearly 50 years ago, the Democratic leanings of the black voters in this belt became apparent. Who knew that 100-million-year-old geologic history could affect voting patterns today?

Blue counties voted Democratic in the 2008 presidential election (Map: New York Times)

Blue counties voted Democratic in the 2008 presidential election (Map: New York Times)

At the “baby field camp” in Southern California, we spent our last five days in a section called Poleta, high in the White Mountains. Trying to understand the gnarled, folded and faulted landscape beyond the first deceptive rise brought many of us to tears. I traced contacts (the boundaries between different rock types) over and over, drawing them where I thought they laid on the map. Eventually, it was necessary to hike out away from the folded hills to hypothesize what might have happened. I remember walking over the last hill, having a rough idea of my conclusions, only to find another fault that changed my thinking.

The sheer frustration of the exercise demonstrated another important point: Maps are hard. They force us to look with a different perspective, to ask tough questions and seek unexpected answers. But what else can we expect from a tool designed to both show and push boundaries?

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Amanda Enbysk is a senior in the College of Earth, Ocean, and Atmospheric Sciences.

 

One Response to “Ground Lines”

  1. Somebody be sure Raven sees this. I think he will get a kick out of it.

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